Tail gas from Claus plants usually contains both H.sub.2 S and SO.sub.2 due to the incomplete conversion of the H.sub.2 S feed in the Claus plant to elemental sulfur. Cleanup of the tail gas means the removal of both H.sub.2 S and SO.sub.2 and conventional processes either reduce the SO.sub.2 in the gas to H.sub.2 S over a cobalt molybdate catalyst in the presence of hydrogen followed by cooling and removing the H.sub.2 S from the cool gas by conventional acid gas scrubbing techniques or by oxidizing the H.sub.2 S to SO.sub.2 followed by cooling and conventional techniques for removing SO.sub.2 such as lime scrubbing. Converting H.sub.2 S to SO.sub.2 requires adding air and preheating the gas to at least 600.degree.-650.degree. C. to insure complete oxidation of the H.sub.2 S to SO.sub.2. U.S. Pat. No. 4,001,375 discloses that cerium oxide can be used to remove sulfur oxides from an oxygen containing flue gas. It would constitute an improvement to the art if one could also use cerium oxide to remove H.sub.2 S and, preferably, if one could simultaneously remove both H.sub.2 S and sulfur oxides. In the case of removing such gases from a Claus plant tail gas, such a process would eliminate the need for separate high temperature combustion of H.sub.2 S or for reducing sulfur oxides to H.sub.2 S, the latter requiring considerable quantities of hydrogen.